Re: Graphic needed to illustrate the effect of access on impact

From: Stevan Harnad <>
Date: Mon, 12 May 2003 19:07:33 +0100 (BST)

Many thanks to Andrew Odlyzko for pointing out the valuable NASA study on
the relation between usage impact and citation impact in astrophysics
(converted to PDF at

This very rich and informative NASA/ADS study confirms what Tim
Brody has also been finding in our analyses of the Physics Arxiv:
and his citation and co-citation analyses with citebase:

See especially Tim Brody's correlator at:

Tim is now working on making this into a variable time-window
correlator, so he can look at correlations in relation to time
at different latencies. We are studying the systematic relationship
between usage and citations, across time. We are also making
Steve-Lawrence-like controlled comparisons with usage/citation patterns
for comparable (1) toll-access paper-only or paper+online
articles versus (2) self-archived open-access articles in order to
demonstrate graphically to all researchers in all disciplines the strong
causal relationship that exists between research access and research
impact, and how and why delay in self-archiving is losing them all
substantial quantities of research impact daily:

Stevan Harnad

---------- Forwarded message ----------
Date: Sun, 11 May 2003 15:19:56 -0500 (CDT)
From: Andrew Odlyzko <>
Subject: benefits of free electronic distribution


A colleague has just sent me a pointer to what appears to be
an important study that carefully documents quantitatively the
benefits of open access to scientific literature. It is a paper
by M. J. Kurtz, G. Eichorn, A. Accomazzi, C. Grant, M. Demleitner,
S. S. Murray, N. Martimbeau, and B. Elwell, "The NASA astrophysics
data system: Sociology, bibliometrics, and impact." It is available


(PostScript only, it appears.) You might like to publicize this
through some of the mailing lists you moderate or have access to.

An interesting tidbit (quoting from the Abstract):

  ... We then introduce the concept of utility time to measure
  the impact of the ADS and the electronic astronomical library
  on astronomical research. We find that in 2002 it amounted to
  the equivalent of 736 FTE researchers, or $250 million, or the
  astronomical research done in France.

Best regards,

Andrew Odlyzko
Received on Mon May 12 2003 - 19:07:33 BST

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